Electrical plug device



Feb. 17, 1942. L. P. CLARK, v.IR

ELEGTRIGAL11=LUG DEVICE Original Filed April 13, 1952 3 Sheets-Sheet 1Feb. 17, 1942. L. P. CLARK, JR

lle'LaECTRI'.CMI` PLUG DEVICE 3 Sheets-Sheet 2 Original Filed April 15,1932 Feb. 17, 1942. l.. P. CLARK, JR

LEGTRIGAL'PLUG DEVICE Original Filed April 13. 193?. 3 Sheets-Sheet 3Reissued Feb. 17, 1942 Re. 22,028 UNITED STATES PATENT OFFICE 22,028 vELECTRICAL PLUGDEVICE Lancaster P. Clark, Jr., Bridgeport, Conn.,assignor t Electric Plug, Incorporated, Bridgeport, Conn., a corporationof Connecticut Original No. 1,979,958, dated November 6, 1934, SerialNo. 604,947, April 13, 1932. Application ior reissue May 3, 1941, SerialNo. 391,812

3 Claims.

Ihe present invention relates to improvements in electrical plugdevices, and has for an object to provide in such a device a plug andcontact unit which may be formed of one piece of metal, Will beinexpensive and reliable in construction, and will provide a positive,rm, and reliable contact. A further object is to provide a constructionin which the plug contact units may be assembled with great facility andwhich when in use will be securely held in the insulating housingagainst` displacement and distortion through the engagement therewith ofthe plug portions of a similar plug device. Another object is to providea housing which may be conveniently molded, and which will have thedesirable characteristics of light weight, compactness and strength, andwhich will at the same time provide ample room for theconvenient'attachment of wires. i

A further object is to provide an electrical plug device in which theplug and contact units each consist of a strip of metal bent upon itselfto form a double thickness plug portion, the two sides of the .stripbeing provided at the base of the plug portion with outwardly bowedportions from which are extended single thickness contact portions,these latter converging into contact with each other when not engaged bya plug portion of an adjacent plug device, and adapted to be spreadthrough such engagement into substantially parallel or surfaceconforming relation, whereby they engage the sides of the inserted plugportion with surface contact.

With the above and other objects in view embodiments of the inventionare shown in the accompanying drawings, and these embodiments will behereinafter more fully described withl reference thereto, and theinvention will be finally pointed out in the claims. f

In the drawings:

Fig. 1 is a side elevation of an electrical plug device, embodying theinvention, and showing in dot-and-dash lines another plug deviceinserted therein. l

Fig. 2 is a plan view of the device.

Fig. 3 is a vertical sectional view, taken along the line 3 3 of Fig. 1.

Fig. 4 is a vertical sectional view, taken along the line 4 4 of Fig. 3.i

Fig. 5 is a perspective View of the plug andresilient contact unit,according to the invention.

Fig. 6 is a. side elevation of the insulating housing employed.

Fig. 7 is a plan View of the insulation housing. Fig. 8 is a plan Viewof the closure plate employed.

Fig. 9 is a plan view of an insulating housing, employed in a modifiedform of the invention.

Fig. 10 is a plan view ployed with the housing as shown in Fig. 11.'

of the closure plate em` Fig. 1l is a vertical sectional view of themodified form ofthe invention employing the housing and coverplatefshown in Figs. 9 and 10. i

Fig. 12 is a side elevation thereof.

Fig. 13 is a side elevation turned 90 from the side, as shown in Fig. 9,and with the closure plate removed.

Fig. 14 is a perspective View of the clamping ring employed in themodification shown in Figs. 9 to 13.

f Fig. 15 is an elevation of a portion of an insulation housing similarto that shown in Fig. 13, but with a modified form of clamping lug.

Fig. 16 is a fragmentary perspective View of a modified form of clampingring for cooperation with the lug illustrated in Fig. 15. i

Fig. 17 is a top plan view, partially broken away, of an electrical plugdevice according to a further modified form of the invention.

Fig. 18 is a side elevation thereof.-

Fig. 19 is a side elevation, turned 90 from the side as shown in Fig.18.

Fig. 20 is a top plan View of the insulating housing employed. l f .i

Fig. 21 is a sectional view, taken along the line 2I-2I of Fig. 19, andshowing rin dot-and-dash lines another plug device inserted therein.

Fig. 22 is a perspective View of the plug and resilient contact unitemployed inthe modication illustrated in Figs. 17 to 21.

Fig. 23 is a plan view of the closure plate employed. v

Similar reference characters indicate corresponding parts throughout theseveral figures of the drawings. v

Referring to the drawings, the insulating housing or shell of the plugdevice, according to the embodiment of the invention illustrated inFigs. 1 to 8, is preferably molded from hard rubber, Bakelite, or othersuitable material, and is of generally cylindrical hollow form,comprising a cylindrical side wall I I.) and a base II, the side wallhaving at its. upper end an outwardly'offset cylindrical portion I2,connected to the main cylindrical portion III by an annular rib I 3,which also serves the triple purpose of providing a ledge for protectingthe edge of the `clamping ring, a continuous annular reinforcement, andi a finger engaging portion for enabling the plug to be convenientlyinserted or removed from a socket element. A lead wire opening I4 isprovided in the side wall I0 extending downwardly from the upper edge,its upper end portion being spanned bythe rib I3. It will be observedthat the inner wall of the portion I2 is substantially flush with theouter surface of the portion Ill, so

-that in molding the housing the opening I4 may be formed by a part onthe mold core fromwhich the housing may be stripped by a straight pull.A vertical partition wall I5 is provided within the opening I4.

formed a single narrow,

2 the housing shell in the central plane intersecting the center of thelead wire opening, a lead wire cut out I6 being provided thereinadjacent The edge of this cutout is designed so that it may also beformed by a portion of the mold core and will not interfere with thestripping of the housing shell from the core by a straight pull. Theupper edge of the portion I2 is provided with a series of projections |1for interlockingly engaging cutoutsin the closure plate, as will Uponthe outer side of said portion I2 `there is slightly projecting, largepitch screw thread I8. The arrangement of this thread in relation to therest of the housing structure is such that it will not interfere withthe strippingv of the housing shell from the mold by a straight pull,the material being sufllciently elastic at the moment of stripping topermit this.

In the base II there is provided in the cornpartment at each side of thepartition wall I5 a relatively thick platform portion I9, having arectangular recess therein and in the base of which is formed a plugreceiving slot 2|. The side walls of the recesses 2.0 are beveled at theupper portions, as at 22, for guiding the contact portions of the plugand contacting units therein, and the exterior edges of the slots 2| arebeveled, as at 23, to guide the entrance of plugs therein. y

A pair of plug and contact devices or units are secured in theAinsulating housing, and each is preferably formed by bending a strip ofsuitable metal upon itself, as at 24, to form a double thicknesssubstantially rigid plugging portion 25, the two legs being bowedoutwardly at the base of the plugging portion, as at 2G and 21, andextended in converging relation to form contact portions 28 and 29. Thebowed portions 26 and 21 provide spring ends for the contact portions 28and 29, so that they may be sprung apart into parallel plug contactingrelation, without bending them between their ends, the spring actiontaking place in the bowed portions. the contact portions 23 and 23 areflared outwardly, as at 30 and 3|, to provide plug guiding surfaces. Theplugging portion 25 is provided adjacent the bowed portions 26 and 21with an extended threaded hole 32 in which a binding post screw 33 isscrewed. In forming the extended threaded hole the side leg at the headside of the screw is punched with a holek slightly larger than the screwand the other side leg is pierced and extended and the opening thereinthreaded.

The plugging portion 25 is provided near its upper end with a hole 34,and the contact portions 28 and 29 are provided with inwardly pressedbosses 35 and 36 respectively, which are adapted to snap into the hole34 of a similar plug unit when the latter is plugged into the device, asshown in Fig. 1.

The cover plate 31 is provided with a pair of slots 38-38 in line withthe slots 2|-2I in the base, and in its periphery there is provided aseries of cutouts 39 adapted to interlockingly engage the projections I1at the upper edge of the housing shell. The cover plate is clamped downupon the housingshell by means of a threaded and flanged clamping ring40, engaged with the thread I8 of the portion I2.

In assembling the plug and contact units the plugging portions 25 areinserted through the slots 38--38 of the cover plate in which theypreferably engage with a snug fit, and the conhereinafter more fullyappear.l

thereupon clamped in place by the clamping ring 4I). In practice thelead wires will be attached to the units before they are inserted in thehousing. It will be observed that the pockets 2li-20 position the unitsvertically while at the same time permitting the contact portions 23-29to be separated upon insertion of a plug between them, asshown'indot-and-dash lines in Fig. 1.

In Figs. 9 to 14 I have illustrated a modification; similar in generalarrangement to the form illustrated inv Figs. 1 to 8, but in which thehousing shell |05 is provided at its upper end with a series of lugs 4Iprojecting upwardly and also projecting laterally and extending for ashort distance downwardly upon the outer surface. The under side 42 isslightly inclined to form the projection into a wedge, and at the lowerend of the incline there is provided a stop lug 43.

The closure plate 44 is provided with slots 45-45 in alignment with theslotsv 2 I-2I of the base, and at its periphery is provided with cutouts 46 adapted to interlockingly engage the lugs 4| of the housingshell. A flanged clamping ring 41 having an outer vertical side andupper and lower laterally disposed flanges is provided in its lowerflange with a series of cutouts 48 adapted to be engaged over the lugs4I and upon turning of the ring to have one end brought into wedgingengagement with the inclined under surface 42 of the lugs to thus clampthe closure plate in place, the stop lug 43 limiting the turning of thering. A cut out 49 in the side and bottom flange registers with the leadwire openy ing I4 in the clamped position of the ring.

The ends of In the modification illustrated in Figs. 15 and 16 the undersurface of the lug 4Ia is corrugated, and the lower flange of :the ring41 is provided with a pressed in boss 50 adjacent the end of the cut out48 for yieldingly engaging the corrugations, the stop lug 43 limitingthe turning of the ring.

In Figs. 17 to 23 I have illustrated a further modification of theinvention comprising an insulating cup-shaped housing shell 5I, the sidewall of which is cylindrical at its upper portion and contracted towardthe base so that it may be conveniently gripped by the fingers. A post52 is integrally formed centrally of the base, its upper end vbeingslightly below the upper edge of the side wall, and reinforcing andguide walls 53 and 54 extend in opposite directions from opposed sidesof the post to the side wall. Diametrically opposed cut outs 55 and 56for lead rwires are provided. in the upper end of the side wall, andcutouts 51 and 58 are provided in the upper ends of the walls 53 and 54for extending lead wires from the binding posts to said openings 55 and5G.

The side wall is provided adjacent the walls 53 and 54 with verticallydisposed channels 59 and 6I), extending downwardly from the top edge andterminating in laterally disposed shoulders or ledges 6I and 62respectively.

Within the base and at opposed sides `of the there are provided slots 53and B4, disposed at-right angles to the walls 53 and 54.

A|pair of plug devices or units are secured in the housing, and 'each ispreferably formed by bending a-strip of suitable metal upon itself,

asat 65, to form a double thickness substantially rigid lpluggingportion 66, the two legs being bowed outwardly at the base of theplugging portion, as at 61 and 68, to form a shoulder, and

portions. The contact portion 69 is bent laterally, as at 1l, and isprovided with an extended threaded hole 12 to receive a binding postscrew 13, and the other contact portion is iiared at its ends, as at1I)a to provide a plug guiding surface.

The plugging portion 6B is provided near its upper end with a hole 13,and the contact portions 69 and 10 are provided with inwardly pressedbosses 14 14 respectively, which are adapted to snap into the hole 13 ofa similar plug unit; when the latter is plugged into the device, asshown in dot-and-dash lines in Fig. 21. The guide Walls 53 and 54, whichextend to the closure plate 16 adjacent th'e slots 80 and 8| eachprovides a guide to insure properly aligned insertion of the pluggingportions.

, In assembling the units the plugging portions 66 are projected throughthe slots 63 and 64 in the base of the housing, the shouldered abuttingthe base at the inner are engaged in ledges El and the channels 62 insuch relat1on as to position A cover plate 16 is seated within the openend of the housing upon the upper end of the post 52 and is providedwithprojecting lips 11 and 18 which engage the lead wire openings, the leadwire openings preferably having ledges 19-19 upon which the lips rest.Plug receiving slots 80 and 8| are provided in the plate in line withthe slots 63 and 64 of the base, and a center hole 82 is providedbetween them in which the securing bolt 83 is engaged, this bolt beingextended through a passage 84 in the post 52, and having a nut 85 uponits threaded end disposed in a countersunk recess 86 inthe lower end ofthe post.

I have illustrated and described preferred and satisfactory embodimentsof the invention, but it will be obvious that changes may be madetherein, within the spirit and scope thereof, as defined in the appendedclaims.

Having thus described my invention what I claim and desire to secure byLetters Patent is:

1. In an electrical plug device, a housing shell of insulating material,having spaced end walls, one or said end walls having a pair oftransversely aligned plug receiving openings and the other ol.' said endwalls having a pair of transversely aligned plug positioning slotshaving their long sides parallel to each other, said housing shellhaving pockets disposed between said end walls and said plug receivingopenings and said be spread at its two sides into parallel relation insurface contact with said inserted plug portion.

2. In an electrical plug device, a housing shell of insulating material,

3. In an electrical plug device, a cup shaped insulating material havinga LANCASTER P. CLARK, JR.

